You've probably heard or belong to the online neighborhood community group Nextdoor. Many people use it to alert others about crime. One person even captured video of a crime in progress, but says he has been ignored by police.

This person thought he had an open and shut case - he had the guy on camera only to find out that police weren't really that interested. But he got a lot of traction online.

A week ago, Peter Spediacci caught a man trying to steal some tools from his San Francisco garage.

The man ran off, but Spediacci had caught it all on his surveillance camera. It shows the thief walking up the driveway, leave later with some goods, and then stop to look inside Spediacci's car.

"I have from the beginning to the end when he left until I caught him and chased him off the property," he said.

Spediacci thought police would have him arrested in no time. He was told to file a police report.

But when he uploaded the pictures onto the online neighborhood community group Nextdoor, dozens of people responded. For many, it was an outlet. They too had been or knew of someone who had been victimized by a criminal.

"My father-in-law was on his way to work at about 5:30 in the morning on 30th and Church and got held up at gunpoint," said San Francisco resident Jeremy Ambers.

When Ambers found out what had happened to his father-in-law, he wrote an email to the Ingleside Police Station.

This is the response he later received:

"No place in this world is completely safe. Crime is on the rise everywhere unfortunately. Law enforcement can only do so much to enforce rules and patrol areas. I'm sorry to hear about your experience. Please exercise caution and be aware of your surroundings."

Officer Giselle talkoff tells ABC7 News, "You have an increase in homeless, you have an increase in mental health issues as well as narcotic issues."

Some neighbors on this thread blame Proposition 47, the 2014 ballot initiative making petty theft a misdemeanor.